Dynamic molecular design for liquid-crystalline materials with a fast response speed

1.显示器件用向列液晶的发展：制备了一种新型的u型液晶分子，其中两个极性间生基团通过儿茶酚，1-{6-（3,4-二氟苯基）己基}-2-{6-[4-（4-氟苯基）苯基]己基}苯连接，并对其电光性能进行了研究。由主液晶（LC）组成的向列相混合物的阈值电压，发现10wt%的u型化合物明显低于主液晶。发现化合物的阈值电压的显著降低是由于介电各向异性的增加。u型系统是一种降低液晶材料阈值电压的新方法。新型宽蓝相区手性液晶：设计了具有分子双轴性的手性液晶低聚物。我们制备了(R)-2,2'-双{6-[4-（2-（2-氟-4-丁氧苯基）嘧啶-5-基）苯氧基]烷基氧基}-1,1'-…More联萘基。在各向同性和SmA相之间较宽的温度范围内，偶原子数的联萘基衍生物表现为手性向列相，而奇数原子数的联萘基衍生物表现为蓝色相。然后，我们制备了一个t形化合物(R)-1-甲基庚-1- 4′-{4-辛基氧基-2-{11-[4-（5-辛基嘧啶-2-基）苯氧基]十一烷基氧基}苯甲酰氧基}联苯基-4-羧酸盐，该化合物在冷却时显示出蓝色相，温度范围宽。具有层次结构的液晶低聚物：制备了一系列新的λ形介晶化合物，其中三个介晶基团与3,4-二羟基苯甲酸相连。发现4-氰联苯基-4′-基3,4-二{6-[4-（5-辛基嘧啶-2-基）苯氧基]己基氧基}behzoate实现了不相称的SmA （SmAinc）相。我们制备了同源双源液晶α-（4-氰联苯-4′-基氧基）-ω-[4-（5-烷基嘧啶-2-基）苯基-4′-氧]烷烃（mPYnOCB）。研究发现，在某些双源化合物的二元混合物中，用不同的奇数间隔剂可以诱导出交叉的抗斜晶C相。此外，在同向热带排列样品的SmCanti相中观察到条纹图案。随着样品温度的变化，条纹图案也随之传播。少

1.Development of nematic liquid crystals for display devices : A novel U-shaped liquid-crystalline molecule where two polar mesogenic groups are connected via catechol,1-{6-(3,4-difluorophenyloxy)hexyloxy}-2-{6-[4-(4-fluorophenyl)phenyloxy]hexyloxy}benzene, was prepared and the electrooptic properties were investigated. The threshold voltage of a nematic mixture consisted of a host liquid crystal (LC) and 10wt% of the U-shaped compound was found to be markedly lower than that of the host LC. Marked reduction in threshold voltage by the compound was found to be attributed to the increase in dielectric anisotropy. The U-shaped system is a novel approach for the reduction in the threshold voltage of liquid-crystalline materials.2.Novel chiral liquid crsyatls with a broad blue phase region : We designed chiral liquid crystal oligomers possessing molecular biaxiality. We prepared a homologous series of (R)-2,2'-bis{6-[4-(2-(2-fluoro-4-butyloxyphenyl)pyrimidine-5-yl)phenyloxy]alkyloxy}-1,1'- … More binaphthyl. The binaphthyl derivatives with an even number of atoms in the spacers showed a chiral nematic phase, however, those with an odd number of atoms showed a blue phase in a relatively wide temperature range between the isotropic and SmA phases. Then, we prepared a T-shaped compound, (R)-1-methylhepthy1-4'-{4-octyloxy-2-{11-[4-(5-octylpyrimidin-2-yl)phenoxy]undecanoyloxy}benzoyloxy}biphenyl-4-carboxylate, which was found to show a blue phase with a wide temperature range on cooling.3.Liquid crystal oligomers with a hierarchical structure : A homologous series of novel λ-shaped mesogenic compounds in which three mesogenic groups are connected to 3,4-dihyrdoxybenzoic acid has been prepared. 4-Cyanobiphenyl-4'-yl 3,4-bis{6-[4-(5-octylpyrimidm-2-yl)phenyloxy]hexyloxy}behzoate was found to realize an incommensurate SmA (SmAinc) phase. We prepared a homologous series of bimesogenic liquid crystals, α-(4-cyanobiphenyl-4'-yloxy)-ω-[4-(5-alkylpyrimidine-2-yl)phenyl-4"-oxy]alkane (mPYnOCB). The interdigitated anticlinic smectic C (SmCanti) phase was found to be induced for some binary mixtures betweeen the bimesogenic compounds with a different odd-numbered spacer. Furthermore, a striped pattern was observed in the SmCanti phase of a homeotropically aligned sample. The striped pattern was propagated when the temperature of the sample was varied. Less